The slab which is supported with Beams and columns is called conventional slab. In this kind of slab the thickness of slab is small whereas depth of beam is large and load is transferred to beams and from beams to columns. It requires more formwork when compared with the flat slab. and there is no need of providing column caps in conventional slab.  The thickness of conventional slab is 4″ or 10cm. 5″ to 6″ inches is recommended if the concrete will receive occasional heavy loads, such as motor homes or garbage trucks. Normally it is square in shape and has a length of 4m. Reinforcement is provided in conventional slab and the bars which are set in horizontal are called Main Reinforcement Bars and bars which are set in vertical are called Distribution bars. hese types of slabs are used in constructing floors of multi storeyed building.

Based on length and breadth of Conventional Slab is classified into two types:

One-Way Slab
Two-Way Slab
1. ONE WAY SLAB:

One way slab is a slab which is supported by beams on the two opposite sides to carry the load along one direction.The ratio of longer span (l) to shorter span (b) is equal or greater than 2, considered as One way slab because this slab will bend in one direction i.e in the direction along its shorter span.However minimum reinforcement known as distribution steel is provided along the longer span above the main reinforcement to distribute the load uniformly and to resist temperature and dhrinkage stresses.

In general length of slab is 4m. But in one way slab one side length is 4m and other side length is more than 4m. So it satisfies the above equation. In one way slab main reinforcement is provided in shorter span and distribution reinforcement is provided in longer span. Distribution bars are cranked to resist the formation of stresses.

Example: Generally all the Cantilever slabs are one Way slab. Chajjas and verandahs are an practical example of one way slab.

. TWO WAY SLAB:

Two way slab is a slab supported by beams on all the four sides and the loads are carried by the supports along both directions, it is known as two way slab. In two way slab, the ratio of longer span (l) to shorter span (b) is less than 2.The slabs are  likely to bend along the two spans in this load is transferred in both the directions to the four supporting edges and hence distribution reinforcement is provided in both the directions.

In this kind of slab the length and breadth of slab is more than 4m. So distribution bars are provided at both the ends in two way slab. To resist the formation of stresses.

These types of slabs are used in constructing floors of multi storeyed building.